Hardware manual

6-2 Agilent 7500 Series ICP-MS Hardware Manual
6 Technical Information
Peristaltic Pump and Tubing
The standard peristaltic pump of the Agilent 7500 has three channels to set
tubing for the sample solution, internal standard solution, and the spray
chamber drain.
There are three types of peristaltic pump tubing:
• Tygon for sample uptake (white/black, 1.02 mm i.d.)
• PharMed for the drain (yellow/blue, 1.524 mm i.d.)
• Tygon for the internal standard (orange/red, 0.19 mm i.d.)
The colors refer to the peristaltic pump head- stops bonded to the tubing.
The Tygon and PharMed tubing are standard issue. The Tygon tubing can be
used for almost all reagents including HF. However, there is a minor
contamination problem with Sn; about 100 ppt Sn was measured when 1%
HNO
3
was analyzed after being pumped through new Tygon tubing. Sn elution
can be reduced to a negligible level by washing with HNO
3
or HCl before use.
The lifetime of the Tygon tubing is about two to three weeks when 1% (v/v)
HNO
3
is pumped; it depends on the acid concentration analyzed and on the
shoe pressure of the peristaltic pump. When higher concentrations of acid are
introduced, the tubing swells and becomes white in color. However, this
change of color does not cause any contamination or affect the analysis.
PharMed is a good material for use with almost all reagents and has a lifetime
about 10 times longer than silicone. However, there are many impurities in it,
therefore it cannot be used for sample introduction, only for the spray
chamber drain.
The sample uptake rate at 0.1 rps peristaltic pump speed is about 0.4 mL/min
with 1.02 mm i.d. tubing. The sample uptake rate linearly increases as a
function of the peristaltic pump speed up to 0.5 rps; 2.0 mL/min is the
maximum sample uptake rate. 0.1 rps is recommended as the standard
peristaltic pump speed, and 0.5 rps for faster sample exchange and wash out.
CAUTION
Some chemicals attack the peristaltic pump tube. This might cause leakage in the
sample introduction and drain lines and corrosion of the sample introduction system.